Why does a twin charger only charge one battery at a time?

110610 GSMGPRSUMTSHSPA Module User Manual SP90MUG trimble dual slot battery charger manual The Dual slot battery charger is supplied with it's own user instructions and is therefore not decribed in this user guide Refer to the Charger Kit Dual Slot trimble charger dual battery slot Be sure to follow all instructions that are provided with the battery charger For more information refer to the Trimble Charger kit dual slot user guide

slot ruby Charge the battery completely before using it for the first time B Tip